Intravascular hinge stent

Abstract

The hinge stent is a balloon-expandable or self-expandable intravascular endoprosthesis used for treatment of vascular injury. The hinge stent is formed of a single stent section or of multiple stent sections joined together. Each stent section has a node and strut structure extending throughout in order to uncouple expansion forces of the stent to hold a blood vessel outward from crush forces that resist the formation of an oval shape during a crush deformation. Each node includes a hinge which is joined via a transition region to a strut. The hinge can bend in the direction of a uniformly curved surface of the stent but not in the radial direction. The strut can bend in the radial direction but not in the uniformly curved surface of the stent. The widths, lengths, and radial dimensions of the hinges and struts provide a balloon-expandable hinge stent that is non-crushable. For a self-expandable stent the hinge and strut dimensions provide expansion forces that are controlled independently from crush forces. The hinge stent can be formed of a high modulus metal with expansion properties being determined by the hinge dimensions and crush properties being determined independently: by the design of the strut dimensions. The node and strut structure of the hinge stent provides for flexibility in traversing along tortuous passages.

We claim:  
     
       1. A wall structure for a tubular member that is deliverable to the site of a lesion within a tubular vessel of the body, the tubular member having a smaller nondeployed state with a nondeployed perimeter and capable of undergoing an expansion deformation to a larger deployed state with a deployed perimeter and being implanted within the tubular vessel in order to hold the wall of the tubular vessel outward, said wall structure comprised of; 
       A. nodes and struts with each of said struts extending between two of said nodes,  
       B. each of said nodes having at least one hinge, said hinge having a hinge radial dimension that is greater than the strut radial dimension wherein said hinge is unable to bend substantially in the radial direction and said struts flex elastically in the radial direction upon exposure to a deformation force that changes the radius of curvature of the tubular member.  
     
     
       2. The wall structure of  claim 1  wherein said hinge has a hinge width that is less than a strut width such that said struts pivot on said hinges in a uniform curved surface of the tubular member during the expansion deformation and said struts do not bend substantially in the uniform curved surface in a direction of the strut width. 
     
     
       3. A wall structure for a tubular member that is deliverable to the site of a lesion within a tubular vessel of the body, the tubular member having a smaller nondeployed state with a nondeployed perimeter and capable of undergoing an expansion deformation to a larger deployed state with a deployed perimeter and being implanted within the tubular vessel in order to hold the wall of the tubular vessel outward, said wall structure comprised of; 
       A. nodes and struts with each of said struts extending between two of said nodes, said nodes being comprised of at least one hinge and said nodes not bending substantially in a radial direction,  
       B. said hinge having a hinge radial dimension which does not allow said hinge to bend substantially in a radial direction upon exposure to a deformation that changes the radius of curvature of the curved surface of said tubular member and a hinge width which allows said hinge to bend within the curved surface of said tubular member due to the expansion deformation,  
       C. each of said struts having a strut width which does not allow said struts to bend substantially in a direction along the curved surface of the tubular member in the direction of the strut width and a strut radial dimension which allows said struts to bend elastically in the radial direction upon exposure to a deformation that changes the radius of curvature of said tubular member,  
       whereby said wall structure provides an uncoupling of the expansion force of said hinge from the elastic radial bending force of said strut such that these forces can be varied independently from one another.  
     
     
       4. The wall structure of  claim 3  wherein said wall structure in the nondeployed state comprises a first node which is adjacent and positioned substantially axially to a second node, said first node not being joined to said second node by a strut having significant axial componency, thereby providing bending flexibility to said wall structure to allow for axial extension of at least a portion of said tubular member for bending around tortuous turns of a tubular vessel of the body. 
     
     
       5. The wall structure of  claim 4  wherein a first hinge of said wall structure controls said bending flexibility independently from a second hinge which controls the expansion force of said tubular member. 
     
     
       6. The wall structure of  claim 3  wherein said wall structure in the nondeployed state comprises a first node which is adjacent and positioned substantially axially to a second node, said first node and said second node forming a portion of a closed loop structure comprised of struts having substantial circumferential componency thereby providing bending flexibility to the wall structure to allow for axial extension of at least a portion of said tubular member for bending around tortuous turns of a tubular vessel of the body. 
     
     
       7. The wall structure of  claim 3  wherein said wall structure in the deployed state comprises a first node which is adjacent and positioned substantially axially to a second node, said first node not being joined to said second node by a strut having significant axial componency thereby providing bending flexibility to said wall structure to allow for axial extension of at least a portion of said tubular member for bending around tortuous turns of a tubular vessel of the body. 
     
     
       8. The wall structure of  claim 7  wherein a first hinge of said wall structure controls said bending flexibility independently from a second hinge which controls the expansion force of said tubular member. 
     
     
       9. The wall structure of  claim 3  wherein said wall structure in the deployed state comprises a first node which is adjacent and positioned substantially axially to a second node, said first node and said second node forming a portion of a closed loop structure comprised of struts having substantial circumferential componency thereby providing bending flexibility to the wall structure to allow for axial extension of at least a portion of said tubular member for bending around tortuous turns of a tubular vessel of the body. 
     
     
       10. The wall structure of  claim 3  wherein said wall structure comprises adjacent nodes which are axially adjacent to each other, said adjacent nodes being joined to each other at least in part by struts not having significant axial componency thereby allowing for axial movement between said adjacent nodes. 
     
     
       11. The wall structure of  claim 3  wherein at least one of said nodes comprises a barb. 
     
     
       12. The wall structure of  claim 3  wherein said barb is held in a folded conformation by said struts in a nondeployed state and is released by said struts upon achieving a specific strut deployment angle, said barb extending outward to substantially its fullest extent upon release. 
     
     
       13. The wall structure of  claim 3  wherein said specific strut deployment angle is intermediate between a strut deployment angle in a deployed state and a nondeployed state. 
     
     
       14. The wall structure of  claim 3  comprising struts aligned in substantially a circumferential direction in a nondeployed state, said struts being rotated about a hinge during deployment such that they align in substantially a circumferential direction in a deployed state that is opposed to their original direction, whereby said wall structure is provided with a large expansion ratio. 
     
     
       15. The wall structure of  claim 3  comprising pivoting struts having substantial circumferential componency, said pivoting struts unfold during deployment such that they have substantial axial componency, said pivoting struts having substantial circumferential componency in a deployed state, whereby the unfolding of said struts provides the wall structure with a large expansion ratio. 
     
     
       16. The wall structure of  claim 3  wherein the said hinges are formed of a plastically deformable material to provide a plastic deformation as said hinges deform during the expansion deformation from the smaller nondeployed state to the larger deployed state. 
     
     
       17. The wall structure of  claim 16  wherein said struts are formed of an elastically deformable material such that said struts bend elastically in the radial direction due to an elastic crush force and return to the original shape upon removal of the crush force, thereby providing a tubular member that is balloon expandable but riot crushable. 
     
     
       18. The wall structure of  claim 16  wherein said hinges have an expansion yield force in the uniform curved surface and said struts have an outward crush elastic force in the radial direction that are uncoupled from each other thereby allowing these forces to be adjusted independently from each other. 
     
     
       19. The wall structure of  claim 3  wherein said hinges and struts are formed of an elastically deformable material, said hinges providing an elastic expansion force in the uniform curved surface of the tubular member that is uncoupled from a crush elastic force provided by said struts in a radial direction. 
     
     
       20. The wall structure of  claim 19  wherein said hinge provides an elastic expansion force to the tubular member outward against the tubular vessel of the body which is larger than the crush elastic force of the tubular member provided by the strut to resist an external crush force, thereby allowing the tubular member to reversibly form an oval shape while maintaining the deployed perimeter. 
     
     
       21. The wall structure of  claim 3  wherein the hinge width and hinge radial dimension of any of said hinges, and the strut width and strut radial dimension of any of said struts are adapted to have different hinge width and hinge radial dimension than another of said hinges and different strut width and strut radial dimension than another of said struts. 
     
     
       22. The wall structure of  claim 3  wherein the hinge width of said hinges located near an end of the tubular member have a smaller hinge width than the hinge width of said hinges located in a mid-portion of the tubular member. 
     
     
       23. The wall structure of  claim 3  wherein the strut radial dimension of said struts located near an end of the tubular member can have a smaller strut radial dimension than the strut radial dimension in the mid-portion of the tubular member. 
     
     
       24. The wall structure of  claim 3  wherein the strut width of said struts located near an end of the tubular member have a smaller strut width than the strut width of said struts located in a mid-portion of the tubular member. 
     
     
       25. The wall structure of  claim 3  wherein the hinge radial dimension of said hinges located near an end of the tubular member have a smaller hinge radial dimension than the hinge radial dimension in the mid-portion of the tubular member.